Psychological research demonstrates how our perceptions and cognitions are affected by context, motivation, expectation, and experience. A mounting body of research has revealed the many sources of bias that affect the judgments of experts as they execute their work. Professionals in such fields as forensic science, intelligence analysis, criminal investigation, medical and judicial decision-making find themselves at an inflection point where past professional practices are being questioned and new approaches developed. Workplace investigation is a professional domain that is in many ways analogous to the aforementioned decision-making environments. Yet, workplace investigation is also unique, as the sources, magnitude, and direction of bias are specific to workplace environments. The workplace investigation literature does not comprehensively address the many ways that the workings of honest investigators' minds may be biased when collecting evidence and/or rendering judgments; nor does the literature offer a set of strategies to address such happenings. The current paper is the first to offer a comprehensive overview of the important issue of cognitive bias in workplace investigation. In it I discuss the abilities and limitations of human cognition, provide a framework of sources of bias, as well as, offer suggestions for bias mitigation in the investigation process.